It has long been recognized as beneficial to patient recovery that exercise or physical therapy begin as soon as possible after an operation to replace or repair an injured joint or limb. It has traditionally been popular to use a conventional orthopedic traction frame similar to that disclosed in U.S. Pat. No. 4,551,872 to Reed to assist a patient in performing remedial exercises. For example, U.S. Pat. No. 3,612,042 to Fry uses a fixed traction frame and adds a number of attachments, such as a swivel assembly and a series of members, to allow a patient to passively exercise his hip while remaining in the hospital bed.
Similarly, U.S. Pat. No. 4,602,618 to Berze discloses the use of a continuous hip-joint motion machine which is attached to a hospital bed. The machine also uses a fixed traction frame to support a series of pulleys which cooperate with the machine to passively exercise the hip joint after replacement surgery.
U.S. Pat. No. 2,855,199 to Noland et al., discloses a progressive resistance device which is removably mounted to a table for exercising both the hamstring and quadriceps femoris muscle groups.
In addition to exercising or rehabilitating injured joints or limbs, it is also important for physicians, physical therapists and exercise physiologists to be able to quantitatively measure and test the strength of a patient's joint or limb prior to, and as a result of exercise and/or surgery. Typically, such testing methods include the use of hand-held dynamometers. For instance, an article by Bohannn entitled Knee Extension Torque In Stroke Patients: Comparison of Measurements Obtained With A Hand-Held Dynamometer ("HHD") And A Cybex Dynamometer discloses the difficulty a tester has in holding a HHD steady during testing of knee extension, if the patient comes to maximal force immediately. In addition, the article discloses the importance of the tester's strength and skill in obtaining accurate measurements.
Rather than using a hand-held dynamometer, complicated devices such as U.S. Pat. No. 5,078,152 to Bond et al. have been developed. The Bond et al. patent discloses a method for diagnosis and/or training of proprioceptor feedback in a muscle and joint system of a human patient. The device is a stand alone unit which includes a passive exercise resistance system having a force measuring system and a position measuring system to determine exercise parameters and feed signals to a computer control system which runs a software program to control the exercise to be performed by a patient. Similarly, U.S. Pat. No. 3,374,675 to Keropian discloses an isometric muscle testing apparatus which requires a slide-block to attach a complicated arrangement of a support bar, a tubular channel support member, a positioning bar, a lockable hinge brake, a measuring arm, a split sleeve, and a load cell assembly to a table. This arrangement is unstable and subject to inaccurate results because of the inherent flexing of the apparatus and the torsional force applied to the load cell assembly during testing, due to the number of interconnected bars and rods secured to the table by the slide-block.
Load or traction frames currently available are limited in their ability to be adjusted to accommodate exercise equipment. Specifically, existing traction frames do not possess the structure necessary to allow it to be pivoted about a horizontal axis relative to the hospital bed or physical therapy table. As a result, there are only a finite number of adjustments which can be made to position the traction frame and the associated exercise equipment relative to the patient. Consequently, patients are unable to take full advantage of the benefits of exercise while recovering in a hospital bed.
The ability to test limb strength of a patient is an important indicator of a variety of factors, such as pre-operation versus post-operation strength. It is therefore desirable to obtain the most reliable quantitative results possible. Existing testing methods use either hand-held dynamometers, which are heavily dependant on the strength and ability of the tester or a machine such as a Cybex dynamometer, requiring a patient to be moved from a hospital bed for testing. In addition, such machines compete for limited hospital budgets because of their associated cost. Consequently, hospitals are faced with a choice between using expensive equipment to conduct their tests of patients or rely on a hand dynamometer which makes quantifiable results in repeated tests difficult to achieve.